What is autosomal dominant PKD?

Autosomal dominant PKD is the most common inherited disorder of the kidneys. The phrase "autosomal dominant" means that if one parent has the disease, there is a 50 percent chance that the disease gene will pass to a child. In some cases-perhaps 10 percent-autosomal dominant PKD occurs spontaneously in patients. In these cases, neither of the parents carries a copy of the disease gene.

Many people with autosomal dominant PKD live for several decades without developing symptoms. For this reason, autosomal dominant PKD is often called "adult polycystic kidney disease." Yet, in some cases, cysts may form earlier in life and grow quickly, causing symptoms in childhood.

Picture of polycystic kidney, roughly retains the same shape as the healthy kidney.

The cysts grow out of nephrons, the tiny filtering units inside the kidneys. The cysts eventually separate from the nephrons and continue to enlarge. The kidneys enlarge along with the cysts-which can number in the thousands-while roughly retaining their kidney shape. In fully developed autosomal dominant PKD, a cyst-filled kidney can weigh as much as 20 to 30 pounds. High blood pressure is common and develops in most patients by age 20 or 30.